Every hit is NOT a kill shot. Your hit may have pounded his armor around the cockpit....it is modeled in those planes that had it.
The reason you didn't see any hits from his seat, is the film showes your point of view. You can see hit sprites, but its not going to show you the damge, although, I've heard some people say they can see the "blood" for a pilot wound.
Basically, you scored hits, but not enough to take the guy down. Try harder next time
